Displacement timing device



DISPLACEMENT TIMING DEVICE Filed March 18,: 1968 Peten Fkrara "i=1 8:1 am; I 3,471, 59 j T0 expldslve element mvsmbx,

$144 ATTORNEY;

United States Patent 3,471,659 DISPLACEMENT TIMING DEVICE Peter B. Ferrara, 1206 Vermont Road,

Bel Air, Md. 21014 Filed Mar. 18, 1968, Ser. No. 713,680 Int. Cl. H0111 43/24 US. Cl. 200-33 9 Claims ABSTRACT OF THE DISCLOSURE varied by the amount of putty used and the tension of the spring.

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

Some of the disadvantages of existing timers have been that they are generally large in size, expensive to procure and package, deterioration during storage, insecure against detection due to noise in operation caused by their complicated escapement mechanisms.

The present invention is designed to provide a timer that is noiseless in its operation and cheap to produce, as well as simple in operation since it has but one moving part and the time delay is quickly adjusted by regulating the tension of a spring and/or the amount of a plastic mass used to slow down the action of the plunger in completing the electrical contact.

The timer of this invention is especially adaptable for use in booby traps, since it could be submerged in water or buried in the ground, provided the electrical wires are protected.

The timer can further, be made in small size and stored indefinitely, since there is no deterioration of the device by moisture or heat.

The time delay can also be set for minutes, hours or even days; if coupled in series with other similar timers, the time delay could be extended to months.

It is therefore an object of this invention to provide a timing device in which a spring biased plunger when released is forced through a mass of silicone putty to complete an electrical circuit.

It is another object whereby the timing delay of the timer can be regulated by adjustment of the tension on a spring and regulating the amount of putty through which the plunger moves.

It is still another object to provide a timer that is small of size and noiseless in its operation.

A final object is to provide a timer that is cheap to produce, simple in operation and impervious to deterioration.

These and other objects and advantages of the present invention will be fully apparent from the following description when taken in combination with the annexed drawing, in which:

FIG. 1 is an axial section of the timer of this invention and showing means for adjusting tension on the plunger biasing spring;

FIG. 2. is a side elevation showing a modified means for adjusting spring tension;

FIG. 3 is a partial cross section taken along line 3-3 of FIG. 2;

FIG. 4 is a cross section taken along line 4-4 of FIG. 2;

FIG. 5 is a similar view showing a modified form of plunger;

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FIG. 6 is a fragmentary view and showing a modified wire terminal; and,

FIG. 7 is a diagram showing the electrical hook-up of the timer.

Referring in detail to the several figures of the drawing in which like reference numerals designate like parts throughout, reference character 1 indicates, generally, in FIG. 1, the timing device of this invention.

Timing device 1 consists of a lower case 2 made from a non-conductive material.

Case 1 slides in an upper case 3 made of metal.

Lower case 2 is open at its upper end which is provided with an outward flange 4, and upper case 3 is open at its lower end which is provided with an inward flange 5 to engage under flange 4 to limit the telescoping movement of the cases.

A plunger 6 is slidable in cases 2 and 3, as shown.

Plunger 6 is cup-shaped and receives one end of a coil spring 7. The other end of spring 7 is received in a cup 8 which is carried by one end of a thumb screw 9.

An arming wire 10, passing through case 3 and plunger 6 normally holds plunger 6 in unarmed position.

Plunger 6 is provided with a series of openings 11 in its floor as shown.

A contact point 12 is integral with the bottom side 0f plunger 6 and is centrally located.

A contact surface is provided in the bottom of cas 2 and consists of a metal disc 13 having a terminal 14 depending centrally from its bottom side and extending downwardly through the floor of case 2.

A ground terminal 15 is integral with the top side of case 3, as shown, so that electrical contact may be com pleted from terminal 15 to terminal 14 through case 3, spring 7, contact point 12 and disc 13 when contact point 12 touches disc 13.

A silicone putty 16, such as commonly known as Dow Corning Bouncing Putty, is placed in the case 2, as shown.

The operation of the timing device 1 is simple. The device 1 will be connected by attaching leads 17 and 18 (see FIG. 7) to terminals 15 and 14, respectively. A battery 19 is in connection with lead 18 and the other ends of leads 17 and 18 will be connected to an element to be exploded (not shown).

After connections are made, arming wire 10 is pulled out to release plunger 6, which when released, is biased downward by spring 7 which biases between cup 8 and the floor of plunger 6 which then moves downward. Putty 16 will be extended through openings 11 until contact point touches disc 13 to complete the circuit.

Instead of using a terminal such as disc 13 and terminal 14, a thin wire 20 (shown in broken lines) may be stretched diametrically across the casing 2. This wire will then be broken, or touched by contact point 12 to either open or complete an electrical circuit as designed.

The size and number of the openings 11 will control the rapidity of the travel of plunger 6 towards contact disc 13, as well as the tension of spring 7.

If it is desired to obtain a shorter time delay, a modified plunger may be used instead of the cup shaped plunger 6 and is illustrated in cross section in FIG. 5. In this form, the plunger is a spider 21 having arms 21a radiating from a cylindrical body 21b which will offer less resistance in its travel through the mass 16.

Other designs for a plunger are possible as in expedient and the form in FIG. 5 is by way of example only.

A further modification of the timer 1 is shown in FIGS. 2 and 3. In this form, means are provided for setting the time delay for specific intervals, i.e., hours, days, etc., and includes visual means for the setting.

In this form, upper case 3 is provided with an inwardly extending pin 22 adjacent its bottom edge. This pin rides in a longitudinal slot 23 in lower case 2, as shown.

v Inclined bayonet slots 24 branch oil from slot 253 at predetermined points (8 being shown), the uppermost bayonet slot 25 being normal to slot 23.

When not in use, upper case 3 is in its uppermost position so that it may be rotated counterclockwise to permit pin 22 to nest in slot 25.

When setting the timer -1, the upper case 3 is rotated clockwise to move pin 22 out of slot 25 and into slot 23. By pushing down on upper case 3, the pin 22 will be placed at the desired setting and then rotated again counterclockwise wherein pin 22 enters the selected slot 24 and the upper casing 3 held in locked position whereby the tension on spring 7 (shown in FIG. 3) is held constant.

It is therefore apparent that the time delay interval is controlled by: (a) The tension of spring 7, (b) the type of plunger 6 used and (c) the amount of silicone putty in lower casing 2.

A modified terminal is illustrated in FIG. 6 for quickly attaching electrical wires thereto. In this form, the terminal is a clamp 26 having serrated jaws which are pivoted as at 27. The jaws will be spring loaded so that they will be normally urged towards a closed position, a portion of a spring being seen at 28.

While only preferred forms of the invention are shown and described, other forms of the invention are contemplated and numerous changes and modifications may be made therein without departing from the spirit of the invention.

What is claimed is:

1. A displacement timing device comprising a first case having an open end; a second case having an open end and slidable in said first case; means carried by said first and second case limiting the telescopic movement thereof; a first terminal element fixed to said first case; a second terminal element located at the closed end of said second case; a plunger slidable in said first and second cases; a coil spring normally biasing said plunger toward said second terminal in said second case whereby electrical connection may be completed between said first and second terminals; a plastic mass in said second case to retard the movement of said plunger towards said second terminal; adjustable means associated with said first and second terminals for regulating the tension on said coil spring; and a safety means in said first case adapted to lock said plunger in a retracted position therein.

2. A device as claimed in claim 1 wherein said means for limiting the telescopic movement of said cases comprises an outwardly extending annular flange integral with the open end of said second case and an inwardly extending flange integral to the open end of said first case .4 andv adapted to engage under said flange .on said second case when said cases are fully extended.

3. A device as claimed in claim 1 wherein said second terminal element comprises a disc adapted to rest on the floor of said second case and a terminal post fixed to its under side and extending through the floo r of 'said second case. l

4. A device asc laimed in claim 1 wherein said plunger comprises a central body anda series of arms radiating therefrom and adapted to engage one end of said coil spring.

5. A device as claimed'in claim 1 wherein said plunger comprises a cup adapted .to receive said spring therein; a contact point integral with its under side and located centrally thereon and having a series of openings in its floor and arranged circumferentially about said contact point.

6. A device as claimed in claim 1 wherein said second terminal comprises an electrically conductive wire disposed diametrically across said second case and located at a predetermined height from its floor.

7. A device as claimed in claim 1 wherein said adjustable means for tensioning said spring comprises a thumb screw threadable in the closed end of said first case and a cap secured to said thumb screw, said cap receiving one end of said spring whereby said thumb screw is adjustable to move said cap against spring to increase or lessen the tension thereon.

8. A device as claimed in claim 1 wherein said adjustable means for tensioning said coil spring comprises a pin fixed in and extending inwardly of the wall of said first case, there being a longitudinal slot in the wall of said second case and a series of longitudinally spaced slots radiating angularly from said longitudinal slot, said slots being adapted to receive said pin therein whereby 'said cases may be manipulated to cause said pin to enter a radial selected slot to hold said cases against telescopic movement whereby the tension on said spring is set. p

9. A device as claimed in claim 1 wherein said plastic mass consists of a silicone putty.

References Cited UNITED STATES PATENTS 2,570,853 10/ 1 Pierce 293-1 2,755,349 7/1956 Silvers 200-33 2,794,868 6/ 1957 McMorran et a1 200-34 3,179,396 4/1965 Bracken 200 -34 3,424,894 1/1969 Schwartz et al 200-34 H. O. JONES, Primary Examiner 

